1. Field of the Invention
The present invention relates to an image processing apparatus for identifying an attentional part from among image data and performing predetermined processing with respect to the attentional part, and particularly to improvements in processing for identifying the attentional part.
2. Background Art
An art for recognizing a desired object from two-dimensional image data regardless of moving images and static images is emphasized and many applications are expected. Hence, many techniques have been proposed conventionally. One of the techniques is a technique called a template matching method. The template matching method is a technique widely used in actual application examples, but there is a problem that unless information as to what place of image data a desired object is present is given separately, it becomes necessary to scan over the whole image data and processing slows.
Therefore, an art for defining a feature image pattern with respect to a desired object and limiting an area to be scanned from image data used as a target of processing using the defined image pattern has been proposed conventionally. Specifically, there is an example of limiting an area of scanning using “flesh color” as a feature of color or using “elliptic shape” as approximate shape when the desired object is a face of a person.
For example, in an art disclosed in JP-A-2000-48184, after flesh color is extracted, a projection distribution of the area is generated and a face area attempts to be identified by extracting a parabola from the projection distribution.
However, also in the method disclosed in JP-A-2000-48184, there are the following problems. That is, first, it is known that “flesh color” is widely distributed on color space and its distribution range varies depending on a reflection state etc. of light. Also, in the case of utilizing a feature of a shape, it is difficult to extract a shape of a parabola from an edge image for a curve figure which is not a complete circle. This is because there are cases where a contour of a face is blocked by hair etc. and a figure is divided or the contour merges into the background and an edge cannot be detected correctly.
That is, in the conventional method described above, there is a problem that an attentional part for processing such as face detection cannot be identified efficiently.